One interesting use of Greasemonkey is to improve web sites that you don’t like the look of. This is useful feedback to the owners of the sites that are being “improved”.
Guardian Title Goodifier reorders the parts the title on GU pages so that the most useful part (i.e. the headline) comes first.
Guardian Blackener simplifies and darkens the design of GU pages.
Update: Guardian Blackener lasted less than a minute before I uninstalled it. The Title Goodifier is useful tho’.